This is how Thunderwing uses the Dark Spark to corrupt Twilight goes in The Revenge of Thunderwing.
[Thunderwing pins Twilight down]
Twilight Sparkle: No!
Twilight Sparkle: Don't!
Thunderwing: I have to!
[Thunderwing brings out the Dark Spark]
Twilight Sparkle: The Dark Spark?
Twilight Sparkle: But how?
Thunderwing: Haven't got time to explain.
[Thunderwing places the Dark Spark on Twilight's neck and its power corrupts her]
Twilight Sparkle: [bows to him] Lord Thunderwing. I am yours to command.
Thunderwing: Yes. YES! The fourth Alicorn Princess and the weilder of the Element of Magic ARE MINE! Equestria shall hear my name AND TREMBLE!